neighborhood small cells & ultrason open for lte
TRANSCRIPT
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Neighborhood Small Cells & UltraSON Open For LTE
© 2013 Qualcomm Technologies, Inc. All rights reserved.
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Overview
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Strong Mobile Data Demand Requires Extra Capacity
Source: Cisco VNI Mobile, 2012
0
6
12
2011 2012 2013 2014 2015 2016
Exab
ytes
per
Mo
nth
1000X
Overall Mobile Data Traffic Growth
MOBILE NETWORKS NEED TO PREPARE FOR 1000X TRAFFIC GROWTH!
0.6 EB 1.3 EB
4.2 EB
2.4 EB
10.8 EB
6.9 EB
78% CAGR 2011-2016
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Small Cells & Extra Spectrum Are Critical For Reaching 1000x
4
MORE
SPECTRUM IN LOW AND HIGHER BANDS
MORE SMALL
CELLS EVERYWHERE!
Evolve
3G/4G/Wi-Fi
HetNets
Interference Mgmt/SON
Intelligently
Access 3G/4G/Wi-Fi
HIGHER
EFFICIENCY
MORE INDOOR
CELLS INSIDE-OUT DEPLOYMENT
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Progressive Introduction Of Small Cells To Build
Dense Carrier-Grade Network
BRING CARRIER-GRADE NETWORK CLOSER
TO USER FOR NEXT LEAP OF PERFORMANCE
Macros
+ planned
small cells
+ dense
unplanned* small cells
Combined network managed by operator
* Small cells will be deployed in areas of high demand without detailed RF planning. 5
Unplanned small cell Planned small cell
© 2013 Qualcomm Technologies, Inc. All rights reserved.
6
INTEGRATED NETWORK
• Plug-n-play small cells with SON
• Unplanned yet operator-managed
A New Network Deployment Model:
Hyper-dense Neighborhood Small Cells (NSC)
SCALABLE DEPLOYMENT
• Minimal CapEx & OpEx • Leverages existing premises
and backhaul
HIGH CAPACITY
• Significant capacity gains compared to macro-only deployment
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Good Outdoor Coverage Even with Low Small Cell
Penetration
• Commercial 3G small (femto) cells in a suburban neighborhood with 7% penetration
on dedicated channel provides good outdoor coverage – 10 mW pilot TX power*
54
0 m
-115 to -105
-105 to -95
-95 to -85
-85 to -75
-75 to -65
-65 to -55
720 m
• RSCP= -115dBm results in ~700kbps in thermal noise limited case
• Points with RSCP less than -115dBm is not shown on the plots
RSCP [dBm]
*Small cells deployed on a channel different from macrocells
Small cell
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Neighborhood Small Cell OTA Network in San Diego
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Live since Nov 2011
• 20 indoor sites (Dedicated spectrum, 20dBm max transmit power) • Substantial outdoor coverage – high throughput • Key UltraSON features for self-configuration, mobility and interference management
demonstrated
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Neighborhood Small Cells Overview
Capacity Gains
Cell splitting
SINR improvement
User closer to serving cell
Wall isolation for indoor
users
More spectrum
High frequency band
operation
Challenges
Mobility
User experience
Network signaling load
Unplanned deployment / self
configuration
Shared backhaul and QoS
Spectrum availability
Capacity Analysis UltraSON Development
9
© 2013 Qualcomm Technologies, Inc. All rights reserved.
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Simulation Results
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Dense Urban Neighborhood Small Cells Simulation Assumptions
Red: 2 story bldg Blue: 3 story bldg
Green: 4 story bldg Cyan: 5 story bldg
Yellow: 6 story bldg
Dense-Urban Area (Simulation with Apartment Buildings)
Black star: Small cell
Magenta Circle: Mobile
Blue circle: Macrocell
met
er
Notes: a) Small cells are randomly dropped in a apartment statistically
independent of other small cells’ locations b) At most one small cell is dropped in any apartment
Parameter Value
Macrocell ISD 500m
Population Density 20000 per sq km
Number of Apartments per Macrocell
(2 subs per Apt.) 720
User Distribution
70% Indoors/ 30% Outdoors;
Randomly dropped
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Neighborhood Small Cell Capacity Simulation Dense Urban Model Configuration
• Multi-floor apartment blocks placed in a
3-cell macro area
• Each apartment block has two buildings
with a street in the middle
• 10 apartments in each floor in each
building
– Two rows of 5 apts
– Each apt is 10m x 10m with a 1m-wide
balcony
• Detailed RF propagation modeling for
indoors and outdoors
– Indoor propagation based on Keenan-
Motley multi-wall model
– Explicit modeling of internal and external
walls, windows and floor losses
• Internal wall loss: 8dB
• External wall loss: 20dB
• Floor loss: 18.3dB (indoor users only)
0 50 100 150 200 250 300 3500
50
100
150
200
250
300
350ISD=1000m
Birds-eye view
Zoomed-in layout
10m
11m
10m
Apartment Block
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Neighborhood Small Cells Capacity Simulation Baseline (macro-only) vs. Macro+Small Cells Deployments
F1
F2
Macro Network
NSC Network
Macro + Small Cells Deployment
F1
Macro Network
Baseline Macro Deployment
Rel 8 LTE, single 10 MHz LTE carrier at 2 GHz carrier frequency
Rel 8 LTE, 10 MHz carrier for macros at 2 GHz while small cells are deployed in 3.5 GHz
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
0x
20x
40x
60x
80x
100x
120x
140x
160x
180x
0% 10% 20% 30% 40% 50%
DL
Me
dia
n T
hro
ugh
pu
t G
ain
(x)
Small Cell Penetration (%)
DL Median Throughput Gains (LTE dense urban, 10 MHz BW small cells in 3.5 GHz, gains
relative to macros only)
25 UEs/macro 200 UEs/macro
Neighborhood Small Cells Provide Significant DL Capacity
Gains for LTE
Neighborhood Small Cells Offer Scalable Capacity As Demand Increases
• 500m ISD, 720 apartments/cell, 2 subs/apartment. Users randomly dropped, 70% indoor and 30% outdoor, 2x2 MIMO • Gains shown are relative to macro-only baseline. Macros deployed in 10 MHz bandwidth at 2 GHz. Small cells deployed at 3.5 GHz with 10 MHz bandwidth. • Small cell penetration is percentage of total apartments per macrocell (720) with a small cell. For a particular operator, this number cannot exceed its own
market share. For example, an operator with 30% market share can at most have 216 small cells in a macro (assuming no small cell is deployed outside customer premise by the operator).
(360 small cells) (72 small cells)
100x capacity gains at 20% penetration
Simulation Configuration
10 MHz
@ 2 GHz
10 MHz @
3.5 GHz
Macro
Small cell
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Exceeding 1000x Capacity Gain With Dense Neighborhood
Small Cells And More Spectrum
• 500m ISD, 720 apartments/cell, 2 subs/apartment. Users randomly dropped, 70% indoor and 30% outdoor, 2x2 MIMO • Gains relative to baseline with macros only. Macros deployed in 10 MHz bandwidth at 2 GHz. Small cells deployed at 3.5 GHz with 100 MHz bandwidth. • Small cell penetration is percentage of total apartments per macrocell (720) with a Small Cell. For a particular operator, this number cannot exceed its own
market share. For example, an operator with 30% market share can at most have 216 small cells in a macro (assuming no small cell is deployed outside customer premise by the operator).
(360 small cells)
0x
200x
400x
600x
800x
1,000x
1,200x
1,400x
1,600x
1,800x
0% 10% 20% 30% 40% 50%
DL
Me
dia
n T
hro
ugh
pu
t G
ain
(x)
Small cell Penetration (%)
DL Median Throughput Gain (LTE, dense urban, 100 MHz small cells in 3.5 GHz, relative to
macros only) 25 UEs/macro 200 UEs/macro
(72 small cells)
1000x capacity at 20% small cell penetration
Simulation Configuration
10 MHz
@ 2 GHz
100 MHz @
3.5 GHz
Macro
Small cell
15
© 2013 Qualcomm Technologies, Inc. All rights reserved.
© 2013 Qualcomm Technologies, Inc. All rights reserved.
SON Features For LTE NSC
© 2013 Qualcomm Technologies, Inc. All rights reserved.
LTE UltraSON™ Overview
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Mobility Management
• Frequent Handover Mitigation
• Forward handover
• Robust mobility signaling
• Automatic neighbor discovery
Tx Power Management
• Network listen based Tx power Mgmnt.
• UE-assisted Tx power management
Resource and Interference
Management
• Resource partitioning and coordination
• Load balancing between macro and small
cell layer
Backhaul Management
• User prioritization based on backhaul
• Load balancing based on backhaul
• Optimize
Handover
performance
and signaling
load
• Optimize
capacity and
user experience
• Minimize pilot
pollution
• Handle
backhaul
constraints
OBJECTIVE CATEGORY UltraSON FEATURES
© 2013 Qualcomm Technologies, Inc. All rights reserved.
SON Features Help Small Cells Deliver Carrier-Grade
Performance
• In an unplanned/semi-planned deployment, RF environment around each
small cell is different and dynamic
• Small cell needs to be able to respond when it is turned on and continue
to adapt to the changing environment
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AT STARTUP
• Select PCI and configure neighbor list • Calibrate Tx power • Optimize idle re-selection parameters and paging
area
AFTER STARTUP
• Adapt Tx power & update neighbor list • Coordinate & partition resources with other cells • Monitor backhaul quality & prioritize preferred
users • Balance load among different cells
© 2013 Qualcomm Technologies, Inc. All rights reserved.
Main Considerations for Mobility Management for NSC
Facilitate handover to small cells to maximize traffic offload
Key Issues:
Mobile UEs on small cell layer likely to cross cell boundary frequently
Excessive handovers create signaling load and potential outage and hence should be avoided
Small cell to Small cell
Small cell carrier
Overlay Macro carrier
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Frequent Handover Mitigation
• Frequent handovers impact user experience and increased risk of call drop
• Classify users as high speed or ping-pong users based on handover history
• Handover high mobility users to macro layer
• Ping-pong users handed over to macro layer if ping-pongs cannot be
avoided through handover parameter adjustment
• In addition, leverage MRO framework for mobility parameter optimization for improved handover performance
Macrocell
Small Cells
Ping-Ponging UE at the edge of Small Cells
Fast Moving UE crossing coverage of Small Cells
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Tx Power and Resource Management
• Dense small cell deployment results
in:
– Frequent handovers due to pilot
pollution
– Degradation of SINR due to inter-SC
interference
• NSC Tx power management to
eliminate pilot pollution
– Minimize number of handovers with
minimal impact on coverage
• NSC resource management to
maximize capacity
– Resource/interference coordination
to improve user SINR
NSC Coverage Regions: With Pilot Pollution
NSC Coverage Regions: With Pilot Pollution Elimination
6 Hard Handovers along route
2 Hard Handovers along route
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Neighborhood Discovery
• Target PCI to Cell ID mapping
need to be discovered to enable
handover
– Network Listen alone cannot
detect all neighboring target cells
for handover
• Mobile reports and X2 message
exchange can be utilized to
enhance the neighbor cell list
determined via Network Listen
– Leverage the ANR framework
Macrocell2
Macrocell1
Small Cell 1
UE
Small Cell 2
Small Cell 1 can only detect Macrocell1
UE can also detect Macrocell2 and Small Cell 2
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Signaling Enhancements For More Robust Handover
• Allow early termination of T310 timer at UE when strong HO
candidate is available
– UE can be served by the stronger target cell sooner without getting stuck
at source cell
• Target cell to fetch UE context from source cell via X2 in case it is not
already prepared for HO
– Forward Handover
Time
Sig
na
l S
tre
ng
th
SNR threshold for
outage (Qout)
Default RLF Timer
Source Cell
Target Cell
Terminate RLF
timer in presence of
strong target cell
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
Backhaul Management
• NSCs leverage existing backhaul with varying bandwidths
– Backhaul bandwidth availability varies due to backhaul sharing with other traffic (e.g., WiFi) and other users
• NSCs need to ensure priority to backhaul owner traffic to provide optimal user experience
• Backhaul management is done via: – Smart offloading between small cells and macros
by monitoring backhaul quality
– Prioritizing home/enterprise user traffic over other user traffic
Non UEs traffic from backhaul
owner
Internet
Neighborhood Small Cell
Residential Gateway
DOCSIS CMTS or DSL DSLAM
Competing traffic from neighbors
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© 2013 Qualcomm Technologies, Inc. All rights reserved.
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